Filtering out people in google photos using content filter does not appear to work

I am trying to select all pictures that do not feature people using the following content filter

 {
  "filters": {
    "contentFilter": {
      "excludedContentCategories": [
        "PEOPLE",
        "SELFIES",
      ]
    }
  }
}

However, I am puzzled by the results. The selection includes a lot of photos that feature people. One of the example is passport like picture of a person face front which should unmistakably fall into PEOPLE category to my mind at least. I also realise that categorising pictures is a difficult task and there bound to be some miscategorisation, so I do not expect that picture with people not showing faces, or only occupying small part of the picture might appear. However, the results I am seeing when applying the above filter is so random and not selective that it makes me think that this functionality simply is not working.

Maybe I am doing something wrong? Perhaps someone can suggest a better way of selecting pictures without people on them? Thank you.

P.S. I am aware that pictures recently uploaded to google might not have been categorised yet. However, I was applying the filter to my photo collection that was uploaded to Google photos about a month prior to my tests. So I would assume that categorisation would have happened by then.

Solution

I can confirm that there is currently an issue with the PEOPLE content category. Unfortunately, at the moment this category is somewhat inaccurate and does not correctly include most media items with people or persons. Our apologies!

Based on your report we identified the issue and will be addressing it in the next release of the Google Photos Library API. Thank you for reporting it!

I have filed an issue on the issue tracker here: https://issuetracker.google.com/111143493 (You can "star" the issue to be notified if there are any updates.)